调用视频号小店的增值服务接口

https://api.weixin.qq.com/wxa/servicemarket/service/get_service_buyer?access_token=xxx

入参

{

    "appid":"wxa29dccd8aabaadf0",

    "service_id": 2816735804764225537

}

{

    "errcode": 0,

    "errmsg": "ok",

    "buyer": {

        "appid": "wxa29dccd8aabaadf0",

        "service_id": 2816735804764225537,

        "spec_list": []

    }

}

wxa29dccd8aabaadf0有成功订购记录的 但是返回的spec_list却是空 请问是什么情况呢